Azo dyes.



UNITED STATES PATENT OFFICE.

HANS REINDEL, F LUDwIGtSHAFEN-ON-TH'E-RHINE, GERMANY, ASSIGNOR TOBADISCHE ANILIN &' SODA FABRIK, 'OF LUDWIGSHAFEN-ON-THE-RHINE,

GERMANY, A CORPORATION.

520 DYES,

4,126,656. Ito-Drawing.

To all whom it may concern Y of the German Empire, residing atLudwigshafen-on-the-Rhine, Germany, have invented new and usefulImprovements in Azo Dyes, of which the following is a specification.

I have discovered valuable new azo dyes which I can obtain from onemolecular proportion of a tetrazotized para-diamin, one molecularproportion of a phenol meta-sulfonicbody containing hydrogen in the paraposition to the hydroxyl group and one molecular proportion of any otherazo component including for instance,-such compounds as phenol, acresol, 2.5-ami,no-naphthol-7- sulfonic acid,2.8-amino-naphthol-6-sulfonic acid, (acid coupling), andalso a monoazocompound, for instance such as those obtained by combining'a diazotizedamin with 1.8 amino naphthol monoor di sulfonic acid in the presence ofacid. As instances of para-diamins which can be employed according to myinvention, I mention benzidin, ortho tolidin, and parapara-diamino-diphenyl-urea.

My new coloring matters are, in the form of their alkali salts, solublein water, possess very pure shades and are particularly suitable fordyeing slibstantively cotton and also paper pulp which is free fromwood. On moderate reduction with stannous chlorid and hydrochloric acid,they give rise to a para-diamin, an amino-phenol-meta-sulfonic acid bodyand at least one other azo component.

The following examples will serve toillustrate further the nature of myinvention and how it can be carried into practical effect, but theinvention is not confined to these examples. The parts areby weight.

Exam le 1: Diazotii'e 18.4 parts of benzi.-'

din, at rom 0 to 5 C., with 13.8 parts of sodium nitrite in the presenceof a slight Specification of Letters Patent.

Patented Jan. 26, 1915.

Application filed J'une 30, 1913. SrialrNo. 776,560.

excess of hydrochloric acid. Then add, gradually, to the tetrazosolution, While maintaining the same temperature, a solu-' tioncontaining 19.6 parts of the sodium salt of phenol-meta-sulfonic acidand 30 parts of calcined soda in about 400 parts of water. Afterstirring for a shorttime, the formation of the intermediate compound iscomplete. Then add a solution containing 25 parts of2.5-amino-naphthol-7-sulfonic acid dissolved in soda and also containinga further 30 parts of calcined-soda. Stir for.

several hours, salt out the coloring matter, filter it off in the pressand dry it. Itdyes cotton and also paper which is free from wood clear,red shades.

Example 2: Tetrazotize 24.2 parts of para-para7-diamin o-diphenyl-ureaand add.

. analkaline solution containing sufficient phenol-meta-sulfonic acid toform the intermediate compound. Stir for several hours and then add asolution containing 10 parts .of phenol, twelve and a half parts of 35%caustic soda solution and 100 parts of water. Continue stirring for 24hours and then heat the mass and salt out the coloring matter and pressand dry it. It dyes cotton and also-paper free from wood greenish yellowI shades.

Example 3: Allow a solution containing the intermediate compoundobtained .by tetparts of l.8-amino-naphthol-3.6 disulfonicacid in thepresence of acid. Stir for 24 hours, then heat-and salt out and pressand dry the coloring matter, which dyes cotton and also paper free fromwood clear green shades.

The following table illustrates the shades obtainable from othercoloring matters which can be produced according to this in linecoupling) Phenol-m-sul1onic acid. p-p'-D1a,mino-diphenyl-urea2.8-Amino-na hthol-6- rlet sulfonic a d (acid 1 coupling)72-Hydroxy-toluene-4-sultonic acid Benzidin v2.5-Amino-naphthol-7-sultonic acid (alkaline coupling) Phenol-m-sultonica'cid 'Benzidl 1.8-Amino-naphthol-3.&disultonic acid-pniu'anilin Purered.

lGreen.

nitranihn i The last two coloring matters of the above vt/able,p1"oduced respectively from benzidin and ortho-tolidin, are obtained bycombining diazotized. para-nitranilin with1.8-aminonaphthol-3.6-disulfonic acid, in acid solution, and thencombinin the product so obtained, in alkaline solution, with theintermediate'product obtained from the diamin 5 and phenol-meta-sulfonicacid.

Pheno1-m-su1tonic acid }Green Now what I claim is 1. The new azocoloring matters obtainablefrom a tetrazotized para-diamin, one.

molecular roportion of a phenol-meta-sulfonic acid ody containinghydrogen in the para position to the hydroxyl group, and one molecularproportion of any other azo water, dye cotton substantively very pureshades and upon moderate reduction with stannous chlorid andhydrochloric acid give rise to a para-diamin, an amino-phenol-meta-"sulfonic acid body and at least one other azo component. f

f 2. The new azo coloring matter obtain able by combining onemolecular-proportion of tetrazotized benzidin with one molecularproportion of phenol ineta-sulfonic acid and,

in alkaline solution, with one molecular proportion of 2.5-aminonaphthol-7 sulfonic acid, which coloring matter, in the form of itssodium salt, is soluble in water and dyes c tton clear red shades and,upon reduction.

1th s'tannous chlorid and hydrochloric acid gives rise to benzidin,ainino-phenolmetasulfonic acid and an amino derivative of 2.5-

- amino-naphthol-7-sulfonic acid.

In testimony whereof I have hereunto set m hand in the presence of twosubscribing witnesses. I

HANS REINDEL. Witnesses:

' J. Ame. Lnorn,

Josnrn Prism component, wh1ch new colorin matters are, 7 "in the form oftheir alkali sa ts, soluble in

